Evaluation of bituminous mixes in pavement structures interim report I - Analysis of mixes containing siliceous aggregates

Abstract

Sufficient heat can be transported from the surrounding ground to a bridge deck by heat pipes to both reduce the number of freeze-thaw cycles and to reduce the time during which the surface is below freezing. In a computer model of the thermal response of a bridge during a sample month, the use of heat pipes spaced six inches apart reduced the number of freeze-thaw cycles by 58% and the time that the surface was below freezing by 87%. While even higher performance is possible, economic and structural constraints will certianly preclude the elimination of all freezing. A screen covered groove heat pipe using ammonia as a working fluid appears to yield the best performance. Computer models are presented to analyse the performance of such heat pipes and to predict the thermal response of a highway bridge with heat pipes to either idealized or actual meteorological conditions. Recommendations are made for further work.